Coil component and wireless power transmission device provided with same

Abstract

The invention provides a coil component capable of improving transmission efficiency in a central region of a charging region while ensuring a wide charging region. A coil component (1) is provided with a first magnetic body (31), a first coil (C1) disposed on the first magnetic body (31), a second coil (C2) disposed on the first coil (C1) and having an outer dimension smaller than that of the first coil (C1), and a second magnetic body (32) disposed between the first coil (C1) and the second coil (C2) and having an outer dimension smaller than that of the first coil (C1).

Description

Technical Field

[0001] The present disclosure relates to a coil component and a wireless power transmission device including the same. Background Art

[0002] A coil component for a wireless power transmission device is disclosed in Patent Document 1.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 7232960 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] However, the coil component described in Patent Document 1 has a problem that when designed to widen the area where wireless power can be transmitted (charging area), the transmission efficiency in the central area of the charging area decreases.

[0008] Therefore, an object of the present disclosure is to provide a coil component and a wireless power transmission device including the same that can improve the transmission efficiency in the central area of the charging area while ensuring a wide charging area.

[0009] Technical Solution for Solving the Technical Problem

[0010] A coil component according to an embodiment of the present disclosure includes: a first magnetic body; a first coil disposed on the first magnetic body; a second coil disposed on the first coil and having an outer dimension smaller than that of the first coil; and a second magnetic body disposed between the first coil and the second coil and having an outer dimension smaller than that of the first coil.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to improve the transmission efficiency in the central area of the charging area while ensuring a wide charging area. Brief Description of the Drawings

[0013] Figure 1 is a schematic cross-sectional view for explaining the structure of a coil component 1 according to a first embodiment of the present disclosure.

[0014] Figure 2 is a schematic top view of the coil component 1 viewed from the coil axis direction.

[0015] Figure 3 is a schematic top view showing the shape of a conductor pattern formed on one surface 11 of a base material 10.

[0016] Figure 4It is a schematic top view showing the shape of a conductor pattern formed on another surface 12 of a substrate 10.

[0017] Figure 5 It is a schematic top view showing the shape of a conductor pattern formed on a surface 21 of a substrate 20.

[0018] Figure 6 It is a schematic top view showing the shape of a conductor pattern formed on another surface 22 of a substrate 20.

[0019] Figure 7 It is a schematic diagram showing an example of the positional relationship in a plane of a first coil C1, a second coil C2, a first magnetic body 31, and a second magnetic body 32.

[0020] Figure 8 It is a graph showing the relationship between the size and magnetic field strength of the second magnetic body 32.

[0021] Figure 9 It is a schematic cross-sectional view for explaining the structure of a coil component 2 according to a second embodiment of the present disclosure.

[0022] Figure 10 It is a schematic diagram for explaining the positional relationship in a plane of a first coil C1, a second coil C2, a first magnetic body 31, and a second magnetic body 32 in the second embodiment.

[0023] Figure 11 It is a schematic diagram showing the positional relationship between a smartphone and a coil component 2 when the coil component 2 of the second embodiment is applied to a charging system of a smartphone.

[0024] Figure 12 It is a block diagram of a wireless power transmission device 70 using the coil component 1 or 2.

[0025] Figure 13 It is a block diagram of a wireless power transmission device 80 using the coil component 1 or 2.

[0026] Description of symbols:

[0027] 1, 2... Coil components

[0028] 10, 20... Substrates

[0029] 11, 12, 21, 22... Surfaces

[0030] 31... First magnetic body

[0031] 31A... Outer peripheral edge of the first magnetic body

[0032] 32... Second magnetic body

[0033] 32A…Outer peripheral edge of the second magnetic body

[0034] 40…Magnet

[0035] 50…Support body

[0036] 60…Electronic device

[0037] 61…Magnet

[0038] 70, 80…Wireless power transmission device

[0039] 71, 72, 81…Power supply circuit

[0040] 73, 83…Control circuit

[0041] 82…Switch

[0042] 90…Smartphone

[0043] 90a…Back side of the smartphone

[0044] 90c…Camera lens

[0045] 100, 200, 400, 500…Coil pattern

[0046] 110, 120, 130, 140, 150, 160, 210, 220, 230, 240, 250, 260, 410, 420, 430, 440, 450, 460, 510, 520, 530, 540, 550, 560…Turn

[0047] 111~114, 121~124, 131~134, 141~144, 151~154, 161, 162, 211~214, 221~224, 231~234, 241~244, 251~254, 261, 262, 411~413, 421~423, 431~433, 441~443, 451~453, 461~463, 511~513, 521~523, 531~533, 541~543, 551~553, 561~563…Wire

[0048] 301~304, 601~605…Through-hole conductor

[0049] C1…First coil

[0050] C1A…Outer peripheral edge of the first coil

[0051] C1B…Inner peripheral edge of the first coil

[0052] C2…Second coil

[0053] C2A…Outer peripheral edge of the second coil

[0054] C2B…Inner peripheral edge of the second coil

[0055] C3…Power receiving coil

[0056] D1…First opening area

[0057] D2…Second opening area

[0058] E1~E4…Terminal electrodes

[0059] S…Placement surface

[0060] ZC1…Coil axis of the first coil

[0061] ZC2…Coil axis of the second coil Detailed implementation mode

[0062] Hereinafter, while referring to the accompanying drawings, embodiments of the present disclosure will be described in detail.

[0063] Figure 1 is a schematic cross-sectional view for explaining the structure of the coil component 1 of the first embodiment of the present disclosure. In addition, Figure 2 is a schematic top view of the coil component 1 observed from the coil axis direction. Figure 1 represents a schematic cross-section along a line that passes through the center of the coil component 1 shown in Figure 2 and extends in the Y direction.

[0064] As shown in Figure 1 and Figure 2 , the coil component 1 of one embodiment includes a first magnetic body 31, a first coil C1 disposed on the first magnetic body 31, a second coil C2 disposed on the first coil C1, a second magnetic body 32 disposed between the first coil C1 and the second coil C2, and a magnet 40 disposed outside the second coil C2 in the radial direction. The first coil C1 is composed of coil patterns 100 and 200 respectively provided on the surfaces 11 and 12 of a base material 10 made of a PET film or the like. The second coil C2 is composed of coil patterns 400 and 500 respectively provided on the surfaces 21 and 22 of a base material 20 made of a PET film or the like. In Figure 1 , for the sake of convenience of explanation, there are gaps between the components constituting the coil component 1, but these components can also be fixed to each other using an adhesive sheet. For example, the first coil C1 can also be adhesively fixed to the first magnetic body 31 via an adhesive sheet not shown, the second magnetic body 32 is adhesively fixed to the first coil C1 via an adhesive sheet not shown, and the second coil C2 and the magnet 40 are adhesively fixed to the second magnetic body 32 and the first coil C1 via an adhesive sheet not shown.

[0065] Both the first coil C1 and the second coil C2 function as power supply coils for wireless power transmission. The coil axis directions of the first coil C1 and the second coil C2 are in the Z direction. The first magnetic body 31, the first coil C1, the second magnetic body 32, and the second coil C2 are laminated in this order along the Z direction. The first magnetic body 31 and the second magnetic body 32 may also be formed of a sheet-like magnetic material having a relative magnetic permeability of 300 or more. When the power supply frequency using the first coil C1 and the second coil C2 is on the order of 100 to 200 kHz, by using a magnetic material having a relative magnetic permeability of 300 or more as the material of the first magnetic body 31 and the second magnetic body 32, a high inductance can be obtained. On the other hand, in the case of information communication using a coil such as near-field wireless communication (NFC), the general communication frequency is in the MHz band (13.56 MHz in NFC), and when using a magnetic material having a relative magnetic permeability of 300 or more, the loss becomes large. Therefore, it is not suitable to use such a magnetic material.

[0066] In actual use, by placing the electronic device 60 including the power receiving coil C3 on the placement surface S shown in Figure 1 , the first coil C1 or the second coil C2 as the power supply coil is combined with the power receiving coil C3, and power is wirelessly transmitted from the coil unit 1 to the electronic device 60. The first magnetic body 31 and the second magnetic body 32 function as magnetic paths for the magnetic flux generated by the first coil C1 and the second coil C2. The first coil C1 is mainly used to ensure a wide charging area, and the second coil C2 is mainly used to improve the transmission efficiency in the central area of the charging area.

[0067] The outer dimension WC2A of the second coil C2 is smaller than the outer dimension WC1A of the first coil C1. The outer dimension WC1A is the dimension in the radial direction of the first coil C1. As shown in Figure 2 , the outer dimension WC1A in the X direction may also be smaller than the outer dimension WC1A in the Y direction. In this case, the outer dimension WC1A of the first coil C1 may also be defined by the dimension in the X direction with the smallest size. The outer dimension WC2A is the dimension in the radial direction of the second coil C2. In the example shown in Figure 2 , the outer shape of the second coil C2 is circular, but similar to the first coil C1, the outer dimension WC2A of the second coil C2 may also be a shape that varies according to the direction.

[0068] The first coil C1 and the second coil C2 may also be configured such that a first opening region D1 surrounded by the winding region of the first coil C1 and a second opening region D2 surrounded by the winding region of the second coil C2 overlap in the Z direction. The winding region of the first coil C1 is the region where the conductor pattern constituting the first coil C1 exists, and refers to the region between the innermost turn and the outermost turn. The winding region of the second coil C2 is the region where the conductor pattern constituting the second coil C2 exists, and refers to the region between the innermost turn and the outermost turn. In this case, the first coil C1 and the second coil C2 may also be configured to have the same central axis. The size WC1B of the first opening region D1 and the size WC2B of the second opening region D2 may also be different from each other.

[0069] The size WC1B of the first opening region D1 may also have different dimensions in the X direction and the Y direction. In this case, the size WC1B of the first opening region D1 may also be defined by the minimum dimension in the radial direction. In Figure 2 In the example shown, the shape of the second opening region D2 is circular like the outer shape of the second coil C2, and the dimensions in the X direction and the Y direction are the same, but the dimensions in the X direction and the Y direction of the second opening region D2 may also be different. In this case, the size WC2B of the second opening region D2 may also be defined by the minimum dimension in the radial direction. The second magnetic body 32 may also be configured to overlap both the first and second opening regions D1 and D2.

[0070] The outer dimension W31 of the first magnetic body 31 is larger than the outer dimension WC1A of the first coil C1, and the entire first coil C1 overlaps with the first magnetic body 31 in the Z direction. The outer dimension W32 of the second magnetic body 32 is smaller than the outer dimension WC1A of the first coil C1, and a part or the whole of the first coil C1 does not overlap with the second magnetic body 32 in the Z direction. Since the second magnetic body 32 is located between the first coil C1 and the mounting surface S, when the first coil C1 is completely covered by the second magnetic body 32, the efficiency of power transmission decreases. However, in the present embodiment, since the outer dimension W32 of the second magnetic body 32 is smaller than the outer dimension WC1A of the first coil C1, it is possible to suppress being obstructed by the second magnetic body 32, and power transmission can be performed using the first coil C1. The outer dimension W32 of the second magnetic body 32 may also be smaller than the outer dimension WC2A of the second coil C2. In this case, a part or the whole of the second coil C2 does not overlap with the second magnetic body 32 in the Z direction. As Figure 2As shown, the outer dimension W31 of the first magnetic body 31 can also correspond to the difference in the radial dimension of the outer dimension WC1A of the first coil C1, and the dimension in the X direction is smaller than the dimension in the Y direction. In this case, the outer dimension W31 of the first magnetic body 31 can also be defined by the dimension in the Y direction with the smallest dimension. In addition, the second magnetic body 32 can also be circular corresponding to the outer shape of the second coil C2.

[0071] The magnet 40 is arranged in a ring shape along the outer shape of the second coil C2 so as not to overlap with the second coil C2. Here, the ring-shaped arrangement includes not only the state of being arranged in a complete circle but also the state of being arranged as shown in Figure 2 with a part of the periphery of the second coil C2 removed. The magnet 40 is at least fixed in the positional relationship with the second coil C2 in the XY plane direction, and positions the second coil C2 and the power receiving coil C3 by the attractive force acting between the magnet 40 and the magnet 61 provided in the electronic device 60. In the Figure 1 and Figure 2 shown examples, the magnet 40 is supported by a support body 50 made of resin or the like. The magnet 40 can also be arranged so that the whole overlaps with the winding region of the first coil C1. If the whole of the magnet 40 is arranged to overlap with the winding region of the first coil C1, the first opening region D1 of the first coil C1 with a high magnetic flux density is not covered by the magnet 40, and thus the loss generated by the magnet 40 can be suppressed.

[0072] Figure 3 is a schematic top view showing the shape of the conductor pattern formed on one surface 11 of the base material 10.

[0073] As Figure 3 shown, a coil pattern 100 and terminal electrodes E1 and E2 that form a part of the first coil C1 are formed on one surface 11 of the base material 10. The coil pattern 100 has a six-turn structure composed of turns 110, 120, 130, 140, 150, and 160. The turn 110 is located at the outermost periphery, and the turn 160 is located at the innermost periphery. Among them, the turns 110, 120, 130, 140, and 150 are equally divided into four parts in the radial direction by three spiral slits. On the other hand, the turn 160 is equally divided into two parts in the radial direction by one spiral slit. As a result, the turn 110 is equally divided into lines 111 to 114, the turn 120 is equally divided into lines 121 to 124, the turn 130 is equally divided into lines 131 to 134, the turn 140 is equally divided into lines 141 to 144, the turn 150 is equally divided into lines 151 to 154, and the turn 160 is equally divided into lines 161 and 162.

[0074] The wires 111, 121, 131, 141, 151, 161 are continuous wires wound in a spiral for 6 turns and are located on the outermost periphery of each turn. The wires 112, 122, 132, 142, 152, 162 are continuous wires wound in a spiral for 6 turns and are located on the second outermost periphery in each turn. The wires 113, 123, 133, 143, 153 are continuous wires wound in a spiral for 5 turns and are located on the second innermost periphery in each turn. The wires 114, 124, 134, 144, 154 are continuous wires wound in a spiral for 5 turns and are located on the innermost periphery of each turn.

[0075] The outer peripheral ends of the wires 111 to 114 are commonly connected to the terminal electrode E1. On the other hand, the inner peripheral ends of the wires 161, 162, 153, 154 are respectively connected to the through-hole conductors 301 to 304 penetrating the base material 10.

[0076] Figure 4 It is a schematic top view showing the shape of the conductor pattern formed on the other surface 12 of the base material 10, showing the state observed from the side of one surface 11 of the base material 10, that is, the state observed through the base material 10.

[0077] As Figure 4 shown, a coil pattern 200 constituting the remaining part of the first coil C1 is formed on the other surface 12 of the base material 10. The basic pattern shape of the coil pattern 200 is the same as the pattern shape of the coil pattern 100. The coil pattern 200 is a six-turn structure composed of turns 210, 220, 230, 240, 250, 260. The turn 210 is located on the outermost periphery, and the turn 260 is located on the innermost periphery. Among them, the turns 210, 220, 230, 240, 250 are equally divided into four parts by three spiral slits in the radial direction. On the other hand, the turn 260 is equally divided into two parts by one spiral slit in the radial direction. Thus, the turn 210 is equally divided into wires 211 to 214, the turn 220 is equally divided into wires 221 to 224, the turn 230 is equally divided into wires 231 to 234, the turn 240 is equally divided into wires 241 to 244, the turn 250 is equally divided into wires 251 to 254, and the turn 260 is equally divided into wires 261, 262.

[0078] The wires 211, 221, 231, 241, 251, 261 are continuous wires wound in a spiral for 6 turns and are located on the outermost periphery of each turn. The wires 212, 222, 232, 242, 252, 262 are continuous wires wound in a spiral for 6 turns and are located on the second outermost periphery in each turn. The wires 213, 223, 233, 243, 253 are continuous wires wound in a spiral for 5 turns and are located on the second innermost periphery in each turn. The wires 214, 224, 234, 244, 254 are continuous wires wound in a spiral for 5 turns and are located on the innermost periphery of each turn.

[0079] The outer ends of wires 211 to 214 are commonly connected to terminal electrode E2 via through-hole conductors. On the other hand, the inner ends of wires 261, 262, 253, and 254 are connected to through-hole conductors 304, 303, 302, and 301, respectively. Thus, a first coil C1 having a structure in which four wires of 11 turns are connected in parallel is connected between terminal electrode E1 and terminal electrode E2. Thus, the first coil C1 is a planar spiral coil.

[0080] Figure 5 This is a schematic plan view showing the shape of a conductor pattern formed on one surface 21 of the substrate 20.

[0081] If Figure 5 As shown in , a coil pattern 400 and a terminal electrode E3 constituting a part of the second coil C2 are formed on one surface 21 of the substrate 20. The coil pattern 400 is a six-turn structure consisting of turns 410, 420, 430, 440, 450, and 460, with turn 410 being located at the outermost circumference and turn 460 being located at the innermost circumference. Turns 410, 420, 430, 440, 450, and 460 are divided into three equal parts by two spiral slits in the radial direction. Thus, turn 410 is divided into three equal parts into lines 411 to 413, turn 420 is divided into three equal parts into lines 421 to 423, turn 430 is divided into three equal parts into lines 431 to 433, turn 440 is divided into three equal parts into lines 441 to 443, turn 450 is divided into three equal parts into lines 451 to 453, and turn 460 is divided into three equal parts into lines 461 to 463.

[0082] Wires 411, 421, 431, 441, 451, and 461 are continuous wires wound in a spiral shape for 6 turns and are located at the outermost circumference of each turn. Wires 412, 422, 432, 442, 452, and 462 are continuous wires wound in a spiral shape for 6 turns and are located in the middle of each turn in the radial direction. Wires 413, 423, 433, 443, 453, and 463 are continuous wires wound in a spiral shape for 6 turns and are located at the innermost circumference of each turn.

[0083] The outer ends of the wires 411 to 413 are commonly connected to the terminal electrode E3. On the other hand, the inner ends of the wires 461 to 463 are respectively connected to the through-hole conductors 601 to 603 penetrating the substrate 20.

[0084] Figure 6 This is a schematic top view showing the shape of the conductor pattern formed on the other surface 22 of the substrate 20, showing the state observed from the side of one surface 21 of the substrate 20, that is, the state observed through the substrate 20.

[0085] If Figure 6 ​​As shown, a coil pattern 500 constituting the remaining portion of the second coil C2 is formed on the other surface 22 of the substrate 20. The basic pattern shape of the coil pattern 500 is the same as the pattern shape of the coil pattern 400. The coil pattern 500 is a six-turn structure consisting of turns 510, 520, 530, 540, 550, and 560, with the turn 510 being located at the outermost circumference and the turn 560 being located at the innermost circumference. The turns 510, 520, 530, 540, 550, and 560 are all divided into three equal parts in the radial direction by two spiral slits. Thus, turn 510 is divided into three equal parts into lines 511 to 513, turn 520 is divided into three equal parts into lines 521 to 523, turn 530 is divided into three equal parts into lines 531 to 533, turn 540 is divided into three equal parts into lines 541 to 543, turn 550 is divided into three equal parts into lines 551 to 553, and turn 560 is divided into three equal parts into lines 561 to 563.

[0086] Wires 511, 521, 531, 541, 551, and 561 are continuous wires wound in a spiral shape for 6 turns and are located at the outermost circumference of each turn. Wires 512, 522, 532, 542, 552, and 562 are continuous wires wound in a spiral shape for 6 turns and are located in the middle of each turn in the radial direction. Wires 513, 523, 533, 543, 553, and 563 are continuous wires wound in a spiral shape for 6 turns and are located at the innermost circumference of each turn.

[0087] The outer ends of wires 511 to 513 are commonly connected to the terminal electrode E4. On the other hand, the inner ends of wires 561 to 563 are respectively connected to through-hole conductors 603, 602, and 601 that penetrate the substrate 20. Thus, a second coil C2 having a structure in which three 12-turn wires are connected in parallel is connected between the terminal electrode E3 and the terminal electrode E4. In this way, the second coil C2 is a planar spiral coil. In addition, the terminal electrode E3 is also provided on the other surface 22 of the substrate 20, and the terminal electrodes E3 provided on the surfaces 21 and 22 are connected via a through-hole conductor 604. Similarly, the terminal electrode E4 is also provided on one surface 21 of the substrate 20, and the terminal electrodes E4 provided on the surfaces 21 and 22 are connected via a through-hole conductor 605.

[0088] Figure 7 This is a schematic diagram for explaining an example of the positional relationship between the first coil C1, the second coil C2, the first magnetic body 31, and the second magnetic body 32 on a plane.

[0089] In Figure 7 In , the outer edge C1A of the first coil C1, the inner edge C1B of the first coil C1, the outer edge C2A of the second coil C2, and the inner edge C2B of the second coil C2 are indicated by solid lines, and the outer edge 31A of the first magnetic body 31 and the outer edge 32A of the second magnetic body 32 are indicated by dotted lines.

[0090] ​​Figure 7 In the example shown, the entire outer peripheral edge C1A of the first coil C1 is located inside the outer peripheral edge 31A of the first magnetic body 31. That is, the entire first coil C1 overlaps with the first magnetic body 31 in the Z direction. In addition, the entire outer peripheral edge C2A of the second coil C2 is located inside the outer peripheral edge C1A of the first coil C1. However, a part of the winding region of the second coil C2 overlaps with the first opening region D1 of the first coil C1 in the Z direction. The second coil C2 is circular, while the planar shape of the first coil C1 has a long side direction, and furthermore, the first opening region D1 also has a shape elongated in the long side direction of the first coil C1.

[0091] In Figure 7 In the example shown, the first opening region D1 and the second opening region D2 overlap in the Z direction. Specifically, a part of the first opening region D1 overlaps with the second opening region D2, and the remaining part of the first opening region D1 overlaps with the winding region of the second coil C2. Similarly, a part of the second opening region D2 overlaps with the first opening region D1, and the remaining part of the second opening region D2 overlaps with the winding region of the first coil C1.

[0092] In Figure 7 In the example shown, both the outer peripheral edge C1A and the inner peripheral edge C1B of the first coil C1 are non-circular, while the outer peripheral edge C2A of the second coil C2, the inner peripheral edge C2B of the second coil C2, and the outer peripheral edge 32A of the second magnetic body 32 are all circular. The central axis of the first coil C1 and the central axis of the second coil C2 may also coincide with the center of the second magnetic body 32. In Figure 7 In the example shown, the entire second opening region D2 of the second coil C2 overlaps with the second magnetic body 32 in the Z direction. A part of the second magnetic body 32 overlaps with the winding region of the second coil C2. A part of the first opening region D1 of the first coil C1 overlaps with the second magnetic body 32 in the Z direction, and the remaining part does not overlap with the second magnetic body 32. A part of the second magnetic body 32 overlaps with the winding region of the first coil C1.

[0093] The second magnetic body 32 mainly functions as a magnetic path for the magnetic flux generated by the second coil C2. Since the second magnetic body 32 is disposed on the side opposite to the mounting surface S when viewed from the second coil C2, the larger the outer dimension W32 of the second magnetic body 32, the higher the power transmission efficiency between the second coil C2 and the power receiving coil C3. The second magnetic body 32 also functions as a magnetic path for the magnetic flux generated by the first coil C1, but since it is disposed at a position closer to the mounting surface S than the first coil C1, when the outer dimension W32 of the second magnetic body 32 becomes larger, the power transmission efficiency between the first coil C1 and the power receiving coil C3 decreases.

[0094] Figure 8 It is a graph showing the relationship between the size of the second magnetic body 32 and the magnetic field strength.

[0095] In Figure 8 it, the horizontal axis represents the ratio (W32 / WC2B) of the outer dimension W32 of the second magnetic body 32 to the dimension WC2B of the second opening region D2, and the vertical axis represents the relative magnetic field strength of the first coil C1 and the second coil C2. Here, the relative magnetic field strength represents the relative strength of the magnetic field reaching the power receiving coil C3 when a unit current flows through the first coil C1 or the second coil C2, which is a power supply coil, and a value of 1 or more is required for good power transmission.

[0096] As Figure 8 shown, the larger the outer dimension W32 of the second magnetic body 32, the higher the magnetic field strength of the second coil C2. If the value of W32 / WC2B is 0.8 or more, the normalized value of the magnetic field strength of the second coil C2 becomes 1 or more. Considering this, the outer dimension W32 of the second magnetic body can be 0.8 times or more the dimension of the second opening region D2. In particular, when the outer dimension W32 of the second magnetic body is larger than the dimension of the second opening region D2, a higher power transmission efficiency can be obtained. In this case, if the central axis of the second coil C2 coincides with the center of the second magnetic body 32, the second magnetic body 32 overlaps the entire second opening region D2, and all the magnetic flux passing through the second opening region D2 passes through the second magnetic body 32, so a high inductance can be obtained.

[0097] On the other hand, the larger the outer dimension W32 of the second magnetic body 32, the lower the magnetic field strength of the first coil C1. When the value of W32 / WC2B exceeds 1.4, the normalized value of the magnetic field strength of the first coil C1 is less than 1. Considering this, the outer dimension W32 of the second magnetic body can be 1.4 times or less the dimension of the second opening region D2.

[0098] As described above, the coil component 1 of the present embodiment includes the first coil C1 having a large outer dimension WC1A and the second coil C2 having an outer dimension WC2A smaller than that of the first coil C1, and these coils are arranged to overlap each other. Therefore, while ensuring a wide charging area, it is possible to prevent a decrease in the transmission efficiency of the central area of the charging area. Moreover, since the second magnetic body 32 is provided between the first coil C1 and the second coil C2, the power transmission efficiency of the second coil C2 can be improved. Furthermore, since the outer dimension W32 of the second magnetic body 32 is smaller than the outer dimension WC1A of the first coil C1, it is possible to suppress being blocked by the second magnetic body 32 and achieve power transmission using the first coil C1.

[0099] Figure 9It is a schematic cross-sectional view showing the structure of the coil component 2 according to the second embodiment of the present disclosure. In addition, Figure 10 It is a schematic diagram showing the positional relationship on a plane of the first coil C1, the second coil C2, the first magnetic body 31, and the second magnetic body 32 according to the second embodiment.

[0100] As Figure 9 and Figure 10 shown, the coil component 2 of the present embodiment is characterized in that the coil axes of the first coil C1 and the second coil C2 do not coincide, and the position of the coil axis ZC2 of the second coil C2 is offset to one side in the long side direction of the first coil C1 with respect to the central position in the long side direction of the first coil C1. The coil axis of the second coil C2 may overlap with the winding area of the first coil C1, but may also overlap with the first opening area D1 of the first coil C1. Other structures are the same as those of the coil component 1 of the first embodiment.

[0101] In Figure 10 the example shown, the entire outer peripheral edge C1A of the first coil C1 is located inside the outer peripheral edge 31A of the first magnetic body 31. That is, the entire first coil C1 overlaps with the first magnetic body 31 in the Z direction. In addition, the entire outer peripheral edge C2A of the second coil C2 may be located inside the outer peripheral edge C1A of the first coil C1, but a part thereof may also be located outside the outer peripheral edge C1A of the first coil C1.

[0102] In Figure 10 the example shown, the first opening area D1 and the second opening area D2 overlap in the Z direction. Specifically, a part of the second opening area D2 overlaps with an end portion on one side in the long side direction of the first opening area D1, and the remaining part of the second opening area D2 overlaps with the winding area of the first coil C1. A part of the winding area of the second coil C2 overlaps with the first opening area D1 of the first coil C1 in the Z direction. The other end portion in the long side direction of the first opening area D1 does not overlap with the winding area of the second coil C2.

[0103] In Figure 10In the example shown, both the outer peripheral edge C1A of the first coil C1 and the inner peripheral edge C1B of the first coil C1 are non-circular and have a long side direction. In contrast, the outer peripheral edge C2A of the second coil C2, the inner peripheral edge C2B of the second coil C2, and the outer peripheral edge 32A of the second magnetic body 32 are all circular. The coil axis of the second coil C2 coincides with the center of the second magnetic body 32, but the coil axis of the first coil C1 does not coincide with the center of the second magnetic body 32. A part of the second magnetic body 32 overlaps with the winding region of the second coil C2. One end of the first opening region D1 of the first coil C1 on the long side direction side overlaps with the second magnetic body 32 in the Z direction, and the remaining part does not overlap with the second magnetic body 32. A part of the second magnetic body 32 overlaps with the winding region of the first coil C1.

[0104] Thus, in the coil component 2 of the present embodiment, since the position of the coil axis of the second coil C2 is offset with respect to the central position in the long side direction of the first coil C1, the center of the charging region can be shifted from the center of the first coil C1. Therefore, even when the power receiving coil C3 is arranged offset from the center of the coil component 2, a decrease in the power transmission efficiency to the power receiving coil C3 can be suppressed.

[0105] Figure 11 FIG. is a schematic diagram showing the positional relationship between the smartphone and the coil component 2 when the coil component 2 of the second embodiment is applied to a charging system of a smartphone.

[0106] As Figure 11 shown, when the electronic device 60 including the power receiving coil C3 is a part of the smartphone 90, power is wirelessly transmitted from the coil component 2 to the electronic device 60 through the coupling of the first coil C1 or the second coil C2 as the power supply coil and the power receiving coil C3, and this power charges a battery (not shown) in the smartphone 90.

[0107] In most cases, a camera lens 90c is provided on the back surface 90a side of the smartphone 90, and in particular, sometimes the recent camera lens 90c protrudes significantly from the back surface 90a. Thus, when the protrusion exists on the back surface 90a of the smartphone 90, the frame for housing the coil component 2 interferes with the camera lens 90c of the smartphone 90. Therefore, depending on the position of the power receiving coil C3 in the smartphone 90, sometimes the coil axis of the power receiving coil C3 on the smartphone 90 side cannot be aligned with the center of the power supply side coil component 2. In addition, even when an alignment magnet 61 is provided on the electronic device 60, due to the interference of the camera lens 90c, the magnet 61 sometimes cannot function effectively.

[0108] However, in the case where the coil axis of the second coil C2 in the coil component 2 is offset with respect to the first coil C1 as in the present embodiment, even if the power receiving coil C3 is arranged offset from the center of the coil component 1, a decrease in the power transmission efficiency to the power receiving coil C3 can be suppressed. That is, it is not necessary to align the coil axis of the power receiving coil C3 with the coil axis of the first coil C1, and it is only necessary to align it with the coil axis of the second coil C2 arranged offset, and thus, the charging efficiency of the smartphone 90 can be improved.

[0109] Figure 12 FIG. is a block diagram of a wireless power transmission device 70 using the coil component 1 or 2.

[0110] Figure 12 The wireless power transmission device 70 shown includes: the coil component 1 or 2 having the first coil C1 and the second coil C2, a power supply circuit 71 connected to the first coil C1, a power supply circuit 72 connected to the second coil C2, and a control circuit 73 that controls the power supply circuits 71 and 72. The control circuit 73 exclusively activates one of the power supply circuits 71 and 72, thereby realizing power transmission using the first coil C1 or power transmission using the second coil C2.

[0111] Figure 13 FIG. is a block diagram of a wireless power transmission device 80 using the coil component 1 or 2.

[0112] Figure 13 The wireless power transmission device 80 shown includes: the coil component 1 or 2 having the first coil C1 and the second coil C2, a power supply circuit 81 connected to the first coil C1 and the second coil C2, a switch 82 connected between the first coil C1 and the second coil C2 and the power supply circuit 81, and a control circuit 83 that controls the power supply circuit 81 and the switch 82. The control circuit 83 connects one of the first coil C1 and the second coil C2 to the power supply circuit 81 by switching the switch 82. Thereby, power transmission using the first coil C1 or power transmission using the second coil C2 can be performed.

[0113] As described above, embodiments of the present disclosure have been described, but the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure, and of course, those are also included in the scope of the present disclosure.

[0114] For example, the first coil C1 and the second coil C2 may be formed of covered wire instead of a conductor pattern formed on the surface of the base material. In addition, the conductor pattern provided on the surfaces 11 and 12 of the base material 10 or the surfaces 21 and 22 of the base material 20 may be provided on the surfaces 11 and 12 of the base material 10 or the surfaces 21 and 22 of the base material 20 via another material layer including resin in the middle.

[0115] The technology of the present disclosure includes the following structural examples, but is not limited thereto.

[0116] A coil component according to an embodiment of the present disclosure includes a first magnetic body, a first coil disposed on the first magnetic body, a second coil disposed on the first coil and having an outer dimension smaller than that of the first coil, and a second magnetic body disposed between the first coil and the second coil and having an outer dimension smaller than that of the first coil. Accordingly, while ensuring a wide charging area, a decrease in the transmission efficiency in the central area of the charging area can be prevented.

[0117] In the above coil component, it may be that a first opening area surrounded by the winding area of the first coil and a second opening area surrounded by the winding area of the second coil overlap, and the second magnetic body is disposed to overlap with the first and second opening areas. Accordingly, more magnetic flux passes through the second magnetic body, and thus a high inductance can be obtained.

[0118] In the above coil component, it may be that the outer dimension of the second magnetic body is smaller than that of the second coil. Accordingly, a decrease in the transmission efficiency of the first coil can be suppressed.

[0119] In the above coil component, it may be that the outer dimension of the second magnetic body is 0.8 times or more and 1.4 times or less the size of the second opening area. Accordingly, the transmission efficiency of the first coil and the transmission efficiency of the second coil can be balanced.

[0120] In the above coil component, it may be that the outer dimension of the second magnetic body is larger than the size of the second opening area. Accordingly, the transmission efficiency in the central area of the charging area can be improved.

[0121] In the above coil component, it may be that the second magnetic body overlaps with the whole of the second opening area. Accordingly, the transmission efficiency in the central area of the charging area can be further improved.

[0122] In the above coil component, it may be that the second magnetic body overlaps with a part of the winding area of the first coil and does not overlap with a part of the first opening area. Accordingly, the transmission efficiency of the first coil and the transmission efficiency of the second coil can be balanced.

[0123] In the above coil component, it may be that the relative magnetic permeability of the first magnetic body is 300 or more. Accordingly, as the supply frequency using the first coil, a frequency suitable for wireless power transmission can be set.

[0124] In the above coil component, it may be that the relative magnetic permeability of the second magnetic body is 300 or more. Accordingly, as the supply frequency using the second coil, a frequency suitable for wireless power transmission can be set.

[0125] The above-described coil component may also include a magnet disposed along the outer shape of the second coil. Thereby, the power receiving coil can be positioned.

[0126] In the above-described coil component, the entire magnet may overlap with the winding region of the first coil. Thereby, the loss of the first coil caused by the magnet can be suppressed.

[0127] In the above-described coil component, the planar shape of the first coil may have a long side direction, and the position of the coil axis of the second coil may be offset to one side in the long side direction with respect to the central position in the long side direction of the first coil. Thereby, even when the power receiving coil is disposed offset from the center of the coil component, a decrease in the power transmission efficiency to the power receiving coil can be suppressed.

[0128] In the above-described coil component, the first opening region surrounded by the winding region of the first coil may have an elongated shape in the long side direction of the first coil, and the second opening region surrounded by the winding region of the second coil may overlap with an end portion on one side in the long side direction of the first opening region. Even with such a structure, a decrease in the power transmission efficiency to the power receiving coil can be suppressed.

[0129] In the above-described coil component, the coil axis of the second coil may overlap with the winding region of the first coil. Even with such a structure, a decrease in the power transmission efficiency to the power receiving coil can be suppressed.

[0130] A wireless power transmission device according to an embodiment of the present disclosure includes any one of the above-described coil components and a power supply circuit connected to the first and second coils. Thereby, a wireless power transmission device with a wide charging area and high transmission efficiency in the central area of the charging area can be provided.

Claims

1. A coil component, wherein: have: a first magnetic body; A first coil, which is disposed on the first magnetic body; A second coil, which is disposed on the first coil and has an outer dimension smaller than that of the first coil; as well as The second magnetic body is disposed between the first coil and the second coil, and has an outer dimension smaller than that of the first coil.

2. The coil component according to claim 1, wherein The first coil and the second coil are arranged so that a first opening area surrounded by a winding area of ​​the first coil overlaps with a second opening area surrounded by a winding area of ​​the second coil. The second magnetic body is arranged to overlap with the first and second opening regions.

3. The coil component according to claim 2, wherein: The outer dimensions of the second magnetic body are smaller than the outer dimensions of the second coil.

4. The coil component according to claim 3, wherein: The outer dimensions of the second magnetic body are not less than 0.8 times and not more than 1.4 times the dimensions of the second opening region.

5. The coil component according to claim 4, wherein The outer dimensions of the second magnetic body are larger than the dimensions of the second opening area.

6. The coil component according to claim 5, wherein The second magnetic body overlaps the entire second opening area.

7. The coil component according to claim 2, wherein: The second magnetic body overlaps a portion of the winding region of the first coil, and does not overlap a portion of the first opening region.

8. The coil component according to claim 1, wherein The relative magnetic permeability of the first magnetic body is 300 or more.

9. The coil component according to claim 8, wherein: The relative magnetic permeability of the second magnetic body is 300 or more.

10. The coil component according to claim 1, wherein The invention further includes a magnet disposed along the outer shape of the second coil.

11. The coil component according to claim 10, wherein The entire magnet overlaps with the winding region of the first coil.

12. The coil component according to claim 1, wherein The planar shape of the first coil has a long side direction, The position of the coil axis of the second coil is offset to one side in the longitudinal direction relative to the central position of the first coil in the longitudinal direction.

13. The coil component according to claim 12, wherein: The first opening area surrounded by the winding area of ​​the first coil has a shape elongated in the longitudinal direction. The second opening region surrounded by the winding region of the second coil overlaps with an end portion of the first opening region on one side in the longitudinal direction.

14. The coil component according to claim 12, wherein A coil axis of the second coil overlaps with a winding region of the first coil.

15. A wireless power transmission device, wherein: have: The coil component according to any one of claims 1 to 14; and A power supply circuit is connected to the first and second coils.

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